Q10 P. - Organic Chemistry (Mcmurry)

Question

Assign configuration to the following substrate, and show the stereochemistry and identity of the product you would obtain by reaction with water (reddish-brown=Br):

Step-by-Step Solution

Answer

The S substrate reacts with water to form a mixture of R and S alcohols.

Nucleophilic unimolecular substitution reaction S N 1

The ${\mathbf{S}}_{\mathbf{N}}\mathbf{1}$ reaction is a nucleophilic substitution reaction where carbon-halogen bond is broken which results in positively charged carbon, and then nucleophile attacks the carbocation and forms a new bond. Only one reacting species is involved in the rate determining step of the reaction. The term  ${\mathrm{S}}_{\mathrm{N}}1$ stands for substitution nucleophilic unimolecular. The hydrolysis of tert-butyl bromide with aqueous NaOH solution is an example of ${\mathrm{S}}_{\mathrm{N}}1$ reaction.

Identity of the product obtain by S N 1 reaction with water

The S substrate reacts with water to form a mixture of R and S alcohols. The ratio of the enantiomer obtained in the reaction is probably close to 50:50 as shown in the figure given below.

          Substrate                                                    Formation of R and S alcohols